Telecommunications – Transmitter – Noise or interference elimination
Reexamination Certificate
2006-06-06
2006-06-06
Nguyen, Duc M. (Department: 2685)
Telecommunications
Transmitter
Noise or interference elimination
C455S063100, C455S067130, C455S296000, C455S114100, C375S296000, C375S346000, C379S392010, C379S406010
Reexamination Certificate
active
07058368
ABSTRACT:
A method and apparatus for noise cancellation in communications systems. The method is applicable in situations where an interfering signal or noise must be cancelled within a specified bandwidth. A sample of the interfering signal is used to synthesize a cancellation signal which is of equal amplitude but opposite phase to the original interference signal. Introduction of the cancellation signal into the interference signal path results in substantially complete suppression of the interference signal through vector subtraction of the superposed signal fields. Adaptive cancellation is also provided in that the frequency and bandwidth of the cancellation signal can be controlled. The adaptive nature of the cancellation loop also tracks out imbalances between the interference and cancellation signals caused by temperature variation and component tolerances. The adaptive nature of the cancellation system also allows the system to lock onto and track an interfering signal.
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Nicholls Charles T
Roussel Alain
Barnes & Thornburg LLP
Nguyen Duc M.
Nortel Networks Limited
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